docs: def load(self, optional_cfg_files=None):
          """ Actually load the configuation from either the default location or the given directory.
          """
          optional_cfg_files = optional_cfg_files or []
  
          # Guard against coding errors
          if self._loaded:
              raise RuntimeError("INTERNAL ERROR: Attempt to load configuration twice!")
  
          try:
              # Load configuration
              namespace = {}
              self._set_defaults(namespace, optional_cfg_files)
  
              self._load_ini(namespace, os.path.join(self.config_dir, self.CONFIG_INI))
  
              for cfg_file in optional_cfg_files:
                  if not os.path.isabs(cfg_file):
                      cfg_file = os.path.join(self.config_dir, cfg_file)
  
                  if os.path.exists(cfg_file):
                      self._load_ini(namespace, cfg_file)
  
              self._validate_namespace(namespace)
              self._load_py(namespace, namespace["config_script"])
              self._validate_namespace(namespace)
  
              for callback in namespace["config_validator_callbacks"]:
                  callback()
          except ConfigParser.ParsingError as exc:
              raise error.UserError(exc)
  
          # Ready to go...
          self._loaded = True